1. Field of the Invention
The present invention relates to a sheet feeding device, and an image forming apparatus, and, especially, to a configuration of a sheet cassette storing sheets.
2. Description of the Related Art
Conventionally, there has been widely spread an image forming apparatus, such as a copying machine, a printer, and a facsimile, which is provided with a sheet feeding device, and in which a sheet is fed from the sheet feeding device to an image forming portion for image forming. Moreover, such a sheet feeding device has generally had a configuration in which a main body of the image forming apparatus installs a sheet cassette as a sheet storage portion in such a way that the cassette may be pulled out, and a sheet stored in the sheet cassette is fed to image forming portion through a sheet feeding roller.
The sheet cassette has a rear end regulating member which regulates a position of the rear end of a stored sheet in the sheet feeding direction (hereinafter, called the rear end) when the sheet with a size smaller than that of a sheet with the maximum size which may be stored is stored. The sheet cassette also has a side end regulating member which regulates a side end position in a direction (hereinafter, called a width direction) orthogonal to the sheet feeding direction of a sheet.
Such a sheet cassette is configured so that, while the side end of a sheet is regulated by the side end regulating member, the rear end is regulated by the rear end regulating member, and the position of the side end, and that of the point of the sheet of the sheet are always regulated to predetermined positions. Thereby, as the sheet is positioned at a predetermined position when the sheet cassette is stored in the main body of the image forming apparatus, stable feeding of a sheet may be performed with less skewed feeding and position deviations.
Incidentally, the size of the image forming apparatus has been reduced in recent years in order to improve the space efficiency. However, when the size of the image forming apparatus has been reduced as described above, there is a case in which the length of the main body of the image forming apparatus is shorter than that of a sheet with the maximum length, which is used for image forming. In this case, there is caused a state in which a sheet cassette is protruded from the main body of the image forming apparatus when the sheet cassette is installed in the main body of the image forming apparatus. Thereby, when a user who does not use such a long sheet uses an image forming apparatus, or when the image forming apparatus is used without using a long sheet, there has been caused a problem that the space efficiency becomes worse by a portion by which the sheet cassette is protruded from the main body of the image forming apparatus.
Incidentally, in order to solve the problem, there has been a sheet cassette which includes a main cassette, and a slide cassette which is slidably provided into the main cassette, and in which a slide cassette is pulled out for use according to the size of a sheet. In such a telescopic sheet cassette, the sheet cassette is used as it is in a case in which a small size sheet is stored, and a slide cassette is drawn out for use when a large size sheet is stored. Such technology has been disclosed in Japanese Patent Application Laid-Open No. 2004-107009.
In such a conventional sheet cassette, the slide cassette is fixed at a pulling out position, or at a storing position in the main cassette by a fixed portion. Then when the slide cassette is pulled out, or is stored, fixing of the main cassette and the slide cassette by the fixed portion is released.
FIG. 24A and FIG. 24B are perspective views of such a conventional telescopic sheet cassette. In FIG. 24A and FIG. 24B, there are shown a telescopic sheet cassette 102, a main cassette 103, a slide cassette 104 which is installed in such a way that the cassette may be sled into a main cassette, a fixed portion 106, and a rear end regulating member 105.
When a sheet with a small size is stored, the sheet cassette 102 is used in such a way that, as shown in FIG. 24A, the slide cassette 104 is moved to a position at which the size of the cassette 104 is reduced. Moreover, when a sheet with a large size is stored, the sheet cassette 102 is used in such a way that, as shown in FIG. 24B, the slide cassette 104 is drawn out from the main cassette 103. When the size of the sheet cassette 102 is enlarged, or reduced, a fixed portion 106 which fixes the position of the main cassette 103 and that of the slide cassette 104 between each other is released.
For example, when sheets with different sizes are stored in the sheet cassette in such a conventional sheet cassette, the slide cassette 104 is drawn out or stored. When such operation is performed, the size of a sheet to be stored is changed.
When the size of a sheet is changed as described above, a position of the rear end regulating member 105 is required to be changed, wherein the position determines the position of the rear end of the sheet. That is, a work to move the slide cassette, and that to move the rear end regulating member are different from each other in a conventional sheet cassette. Thereby, when the size of the sheet is changed, a user is required to perform two kinds of operations. That is, there has been a problem that the usability is not good.